[SOLVED] Need help Overclocking i7 9700k

MCE mode (all cores at peak 4.9 GHz turbo) is likely too much heat for the NH-D15 to contend with on a 9700K...

Test your temps at Intel's intended stock profile first, i.e, 1-2 cores at 4.9 GHz, 3 or 4 cores at 4.8 GHz, with 7 or 8 cores loaded at 4.6 GHz; a rig I built for a friend on an Asus board with NH-D15 gave 68C under load so equipped, so, we did not even attempt MCE mode, not that he needed it anyway for surfing and MS Office...